Hoisting mechanism.



W.B. GERVAIS.

HOISTING MECHANISM. APPLICATION FILED OCT. 20. 1915.

Patented Aug. 21, 1917.

2 SHEETSS HEET 1'.

I i 14' 1 a UNITED STATES PATENT OFFICE.

'W'AINWBIGH'I IB. GERVAIS, OF CHICAGO, ILLINOIS, ASSIGNOB, '10 VARIETYMANU- FACTURING COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OFILLINOIS.

HOISTING MECHANISM.

Specification of Letters Patent.

Application filed October 20, 1915. Serial No. 56,822.

To all whom it may concern: Be it known that I, WAINWRIGHT B. GER- vAIs,a citizenof the United States, and a resident of Chicago, in the countyof Cook and State of Illinois, have invented a certain new and usefulImprovement in Hoisting Mechanism, of which the following s a full,clear, concise, and exact descript on, reference being bad to theaccompanying drawings, forming a part of this speclfication.

' The present inventionirelates to hoisting mechanism more self-dumpingtruc rs and the like.

The problem of hoisting the end of a self-dumping truck or the like hasalways presented serious mechanical difficulty as it is necessary tohave a powerful. mechanism for hoisting or raising the one end of thebody to dump the-same and it is desirable, after dumping has beenperformed, to restore the parts to the normal condition as quickly aspossible. The'use of screw-]acks or the like demands that almost as muchtime be consumed in lowering the body after dumping has been performedas in raising the same. A number of devices. have been proposed fordisconnecting the lifting or hoisting apparatus when it is desired tolower the body, but this in general has proved undesirable andunsuccessful first, because it is often desired to dump only a part ofthe load and then restore the body to normal condition. A seconddifiiculty arises in that the mechanism required to lower the bodyusually depends upon some cushioning device forstopping the movement ofthe body as it lowers and these devices generally prove unreliable andare sub- 49 ject to breakage and damage upon the first use.

It is with the difiiculties of the prior art in mind that I have devisedthe present in-v vention, the object of which is to provide a powerfulhoisting mechanism which will be able readily and easily, to hoist apowerful load through a given distance and to allow rapid lowering ofall or part of the load without damage to the apparatus, and so withoutexcessive arring. In the accompanying drawings, which form a part of thepresent specification I have illustrated one form of mechanism in whichmy invention may appear. The particular mechanism chosen is applied tothe frame of a truck articularly for use with Windlass is operated andis employed in raising and lowering one end of the truck to accomplishdumping of the contents thereof.

Figure 1 is a front elevation of the same and Fig. 2 is a side elevationof the same.

According to my invention the body that is to be dumped is raised by aback-geared; Windlass'opera'ted by a handle or other suitable means, themechanism thereof being geared to a powerful centrifugal brake. Themovement of the body which is being hoisted is so slow during thehoisting period that the centrifugal brake does not interfere materiallywith the movement and no extra work is necessary to raise the body.During .the downward movement of the body hoisted,

the movement is so rapid that the centrifugal brake is put in operationand prevents more than a predetermined speed of lowermg. The mechanismis so arranged that the more rapidly as the body to be hoisted comesnearer to its normal position so that the brake has a far greater effectat the end of the movement 3f the body in approaching its normalposiion. The frame'of the truck is shown as composed of the channelbeams 1 and 2 which orm the side bolsters of the supporting structure ofthe body, a part of which is shown as the channels 3 and 4 connected bythe channel 5 to form the front end of the tilting body. The tiltingbody which is not shown rests upon andis secured to the beams 3, 4 and5, the beams 3 and 4 being pivoted at a suitable point to the under'frames 1 and 2. The beams 3 and 4 normally rest upon the cast ironbrackets; 6 which are secured to the main frames, 1 and 2 and serve aspivots to the toggle mechanism later to be described. A suitable bracketmember 7 is secured to the beams 3, 4 and 5 on each side of the dumpingbody and a pair of toggle links 8 and 9 connect the brackets 6 and 7.The links 8 and 9 are connected together at their inner ends and arepivoted upon a suitable shaft 10. A heavy an'gle bar 11 is laid acrossthe main channel beams 1 and 2 and is bolted thereto to support theWindlass or hoisting mechanism. A mast 12 which may be formed of I-barsor other suitable structural shape is secured to the cross-beam 11 endbears at its upper end the cross-shaft 13, a pair of pulleys 1 1 and 15being secured,

to the free ends of said shaft and rotatable therewith. The ends of theshaft 13 are braced by suitable struts or su'p orting members 16 and 17and tension mem ers 18 and 19. A piece of T-bar 20 is securedto the topof the mast and is bent at 21 to form a suitable brace or strut 22'which in turn is secured to the cross-bar 11 at its lower end. The strut22 is supported by the two anchor rods 23 and 24 that are secured bysuitable clamps 25, 26 to the beams l and 2. The mast 12 is thus bracedand the pulleys or sheaves 14 and 15 are supported in proper positionfor raising and lowering the body of the truck as will be described.

The. main Windlass shaft 27 hassuitable bearings in the brackets 28 and29 which are bolted to the cross-bar 11. These bearings are preferablyprovided with antifriction rollers to make the operation thereof easier.

The outer left-hand end of the shaft 27 bears a gear 30 which isinclosed in a suitable gear-case 31. The gear 30 meshes with a pinion 32secured to the shaft 33 of the centrifugal governor 34. The casing ofthe centrifugal governor 34 is secured to the gear case 31 whichsurrounds the pinion 32 and also a pinion 35 which is mounted upon thedriving or operating shaft 36. The outer end of the operating shaft 36is squared, as shown in the drawing, and a suitable crank 37 providedwith. a handle 38 fits on said outer squared end. A ratchet wheel 39 issecured to the shaft 36 and a suitable pivoted pawl 40 engages the teethof said ratchet wheel to prevent retrograde movement while the body isbeing hoisted. The shaft of the centrifugal device has a pair of arms 41secured thereto. arms 4-1 bear upon their outer end inertia members 42which arepivoted to the outer end of the arms 41 and are provided withsuitable brake shoes 43 which engage the inn cylindrical surface of thecasing of the centrifugal device 34. The main windlass shaft 27 has pairof chains 44 and 45 secured thereto. The chain 44 passes over the pulle14 and thence down and under a small pu ley or sheave 46 which isrotatably mounted in a suitable bracket 48 secured to the bottom of thedumping body. The other end of the chain 44 is secured to the shaft 10which forms the connecting pivot between the toggle arms 3 and 9. Thechain 45 is similarly trained over the pulley or sheave 15 and thenceunder a pulley 47 carried in a bracket 49 mounted similarly to thebracket 48 on the dump body. The chains 44 cooperate in a manner whichwill readily appear. The operation of the device will now be described.

When the body to be hoisted is in the position shown in Fig. 2, thechains 44 and 45 will in effect pull directly upward upon the These 7menses mast 12 which it is desirable to keep as low as possible forobvious reasons. When the load has been dumped by tilting of the body,as above indicated, it is desired that tlfe body be lowered asquickly aspossible and since the load at this time is not excessive, it isdesirable that a quick descent be made. To accomplish this the pawl 40is disengaged from the ratchet 39 and the handle 37 is released. Thebody descends rather swiftly and in so doing operates the centrifugalbrake 34, the brake shoes 43 rubbing against the inside of the drum andpreventing too rapid descent. When the toggle arms 8 and 9 have swungconsiderably to the left in Fig. 2 the pulley 46 will engage the chain44 and will give a direct pull thereupon. The result of this is atendency to rotate the shaft 27 rapidly and the brake 34 becomeseffective to prevent the same.

A very important action occurs in the diminution of the effectivediameter of the shaft 27 when the body approaches normal position. Thechains 44 and 45 being wound upon the shaft 27 very rapidly increase theeffective radius thereof and the lifting power would be considerablyreduced except for the fact that the toggle 8, 9 comes into play i thelatter part of the action. But the seL-same action secures a highlybeneficial effect in allowing of a rapid descent of the body during thefirst part of its fall and a slower rate of descent during the latterpart of its fall due to the decreased diameter of the winding drum 47caused by unwinding of the chains 44 and 45 therefrom. Thus it can beseen that a given drop of the body spins the Windlass shaft 27 morerapidly when the body approaches the normal position. As a consequencethe brake 34 causes a slower rate of descent of the body as itapproaches the normal position.

While I have described my invention with reference to the details ofconstruction of a particular embodiment, it is to be under stood that myinvention is capable of being embodied in a variety of forms and withnumerous modifications and changes as Will at once suggest themselves tothose skilled in the art. All of these I consider to come within thespirit and scope of my invention.

What I claim is:

1. In combination, a frame, a body to be 130 i u I at till aes'zgsas gg;

hoisted, a roast securedto said frame, a pair of to gle arms secured tosaid body and to said rrame, flexible hoisting means secured to saidtoggle and passing under said body to be hoisted and a Windlass securedto said mast, said Windlass being connected to said flexible hoistingmeans.

2. ln combination, a frame, a mast secured to said frame, a Windlasssecured to said frame and having a flexible hoisting cable passing overthe end of said mast, a body to be hoisted, toggle members connectingsaidbody and said frame, a projection. secured to said body and passingbelow said toggle, said flexible hoisting means being secured to saidWindlass and to said toggle and pass ing under the projection onsaidjbody.

3. In combination, a frame, a mast secured to said frame, a pulleyrotatably mounted adjacent the top of said mast, a body to be hoisted,toggle members connecting said body and said frame, a bracket on saidbody, said bracket projecting below the attaching point of said togglemembers, a Windlass, a centrifugal governor cared to said Windlass and aflexible hoisting cable secured to said Windlass and to said toggle,said cable passing over said pulley adjacent the top of said mast, andunder the bracket secured to said body.

4:. in combination, a frame, a body to be tilted, pivotally secured tosaid frame, toggle arms connected between one end of said body and saidframe, a projection on saidbody adjacent the connection of said toggle,a Windlass, a. centrifugal brake secured to said Windlass and a hoistingcable secured to said Windlass passing under said projection and securedto said toggle members. I

5, The combination with a frame, a body on said frame to be raised, ahoisting drum, an automatic retarder therefor, and driving means for thedrum, of a standard disposed adjacent one end of thebody, pulleys onsaid standard, a pair of toggles connecting said frame with said body, apair of flexible hoisting elements anchored to the drum to be woundthereupon and over said pulleys and having their free ends connected tothe center joints of saidtoggles, whereby upon starting a hoistingoperation, the intermediate portion of the hoisting element will engagebeneath the free end of the body and near the end of a hoistingoperation the toggles will be caused to straighten and complete theraising operation.

ation, and upon said toggle near the end of a hoisting operation.

7. In a hoisting device, the combination with a base frame and a bodythereon to be hoisted, of a hoisting drum and a flexible hoistingelement to be wound thereupon, a

toggle interposed between the frame and said body, the free end of thehoisting element being connected to the toggle joints, and means on theadjacent end of the body to engage the intermediate portion of thehoisting element, whereby at the start of a hoisting operation, actionof the hoisting element will be directly upon the body and at the end ofa hoisting operation the stress will be developed at the toggle joint,to expand the same and raise the body to a point higher than the pointfrom which the flexible element exerts its force and thereby completethe raising operation.

In witness whereof, I hereunto subscribe my name thisloth day of OctoberA. D. 1915.

wainwarenr n. o erate.

